1. Field of the Invention
This application relates to an improved balancing mechanism for adaptation to an internal combustion engine. More particularly, the invention utilizes two oppositely rotating counter balance shafts mounted within a housing which is hang mounted beneath the engine crankshaft and partially submerged in engine lubricating oil. The housing has a plurality of mounting columns which engage the partitions of the engine block which also serve as the bearing support for the crankshaft.
2. Prior Art
There are many different designs and balancing mechanisms for internal combustion engines. Representative patents showing different configurations are described hereinafter.
Some engine balancing mechanisms were patented many years ago and are disclosed hereinafter. U.S. Pat. No. 1,164,267 to Lanchester utilizes two shafts mounted laterally with respect to the axis of the crankshaft and supported by a similarly extending bracket which engages the shaft ends. Unbalanced rotors are supported about the shafts. The U.S. Pat. No. 1,588,720 to Gilbert discloses a balancing mechanism with a piston which is vertically reciprocal in an opposite direction to the usual engine piston. The U.S. Pat. No. 1,658,979 to Fisher is similar to the Lanchester patent by its use of laterally extending shafts mounted by end portions in a laterally extending housing. The U.S. Pat. No. 1,898,459 to Newcomb discloses a balance mechanism with a pair of shafts which extend parallel to the engine crankshaft. The shafts are rotatably mounted between a lower portion of the engine block and an oil pan and are driven by a laterally extending cross-shaft engaging a gear on the crankshaft. The British Pat. No. 674,225 discloses a balancing mechanism somewhat like as shown in the Newcomb patent, but utilizes a frame-type housing to mount lobed balance shafts for rotation. The unbalanced or lobe portions of the shafts are located on both sides of several bearing portions or journals as are provided in laterally extending partitions of the frame.
There are a number of patents which disclose balance shafts which are supported in bearing journals formed in the engine block itself. U.S. Pat. No. 3,308,680 to Sherrick discloses an engine having a balance shaft mounted in the block to one side of the crankshaft. There are unweighted portions supported on the shaft end, and also along the shaft on either side of several bearings for the shaft. Also, U.S. Pat. No. 4,028,963 to Nakamura discloses an engine block with balance shafts mounted for rotation in the engine block above the crankshaft axis. Similar configurations are disclosed in U.S. Pat. Nos. 4,508,069 to Dobler and 4,510,898 to Ampferer.
There are also a number of patents disclosing balance shafts mounted in housings which are, in turn, supported below the engine crankshaft. Two recent U.S. Pat. Nos. 4,440,123 and 4,480,607 utilize an Oldham coupling device to provide engine balancing instead of more conventional balance shafts. U.S. Pat. Nos. 2,914,963 and 2,914,964 disclose balance shafts with rotatable weight portions rotated thereabout and the shafts are mounted in a housing which is hung from a portion of one of the main bearing journals for the crankshaft. U.S. Pat. Nos. 2,688,839 to Daub; 2,914,137 to Sykes; and 4,300,493 to Berti disclose balancing mechanisms in housings which are located beneath the crankshaft.